<!doctype html>
<html>
<head>
<style>
button {
position:relative;
padding:0;
background:green;
width: 200px;
height: 100px;
border:none;
text-align: left;
font: 12px serif;
-moz-appearance: none;
border-radius: 0 !important;
}
button span {
display:block;
position:absolute;
right:0;
top:0;
width:10px;
height:100%;
background:red;
}
</style>
</head>
<body>
<button>
<span></span>
</button>
</body>
</html>
